The passing of lyricist Hal David at 91 did not mark the end of an era in American popular culture. That era — defined as much by generosity, gallantry and decency as by unforgiving rivalries — ended long ago. But somebody forgot to tell Hal, my friend of 25 years.

Hal, a gentleman and a patriot, carried on until the moment of his death Saturday as if the music industry, never known for saintly behavior, had not devolved into a cesspool of drugs, depravity, litigation, rap-world assassinations — and unintelligible lyrics.

His art was built on mastery of craft, a step typically omitted today. It commanded the cathartic power of language. Wed to music by Burt Bacharach and others, it invested themes of heartbreak, loss and human yearning with a simple eloquence alien to the 21st Century’s self-absorbed, politically cranky, rage-expending singer-songwriters.

Hal had no use for political pandering. Of one of his and Bacharach’s hits for Jackie DeShannon, Hal later said the main theme came to him easily: “What the world needs now is love sweet love . . .”

But he struggled over what came next. “I kept thinking of lines like, ‘Lord we don’t need planes that fly higher and faster,’ ” he wrote later, before he came up with “Lord we don’t need another mountain,” and the rest about meadows and cornfields and wheat fields.

Hal wrote those lyrics in 1965, at the onset of the Vietnam War. A less assured songwriter might have dragged in bombers and napalm. Even his only “political” number, “Windows of the World,” reads more as a father’s worry for his draft-age sons than as an indictment of US policy.

Hal was so normal, I had to remind myself of being in the presence of an Oscar-winning genius. He did without fixers and flunkies in an age when reality-TV jerks don’t get out of bed without an entourage. So lightly did he wear his fame, a restaurant where we helped him and his wife get a table mistook them for tourists, seating them in a dark corner of Siberia before wiser heads prevailed.

Hal worked for the New York Post as an advertising copywriter from 1942-43, a brief turn he recalled with disproportionate enthusiasm. Drafted into the Army, he cited his “writing experience” at The Post to land a gig in an entertainment unit which proved to be the springboard for his music career.

But he’d also taken journalism courses at NYU and would have made a helluva reporter. He named as the building blocks of his art “believability, simplicity and emotional impact” — qualities at the heart of tabloid writing.

Hal was fiercely faithful to his country, to his family — and to New York. Although he sold his apartment here a few years ago, he loved the city enough to risk a trip from his home high above Los Angeles last month after major surgery.

“It’s been a struggle,” he told me. “But I’m glad I came.”

We both were raised in once-sound Brooklyn neighborhoods now blighted. Although aware that the city overall was better, he lamented that his boyhood stamping ground was reduced to ruin.

We talked of making an expedition together to our childhood precincts, hoping we’d find signs of progress. But he told me of once going to the East New York block where he grew up with filmmakers working on the story of his life.

“They were afraid to get out of the car,” he laughed sadly.

Time ran out on our plan. But I’ll make the journey for him — and maybe, in due time, report back to Hal with better news of the streets he still missed.